Abstract: In order to study the characteristics of hypersonic inlet response to rapid periodic dynamic angle of attack, numerical simulations are performed on 2D hypersonic inlets with dynamic angles of attack. The effect of dynamic angle of attack on unsteady aerodynamic characteristics is analyzed at a Mach number of 4.03. Two cases of the angle of attack motion are considered. In the first case, the inlet moves upward at a constant angular velocity, while in the second case it repeats a cyclic motion. The investigation suggests that: For dynamic increase of the angle of attack, similar to the steady cases，the characteristics of the flow field and the performance of the inlet are significantly altered, while the unsteady flow field feature and performance lag behind the steady cases. In the first case, the value of the angle of attack at unstart tends to increase with the rising of the angular velocity. In the low flow-speed area near the bottom wall, the impact of the unsteady flow on the aerodynamic characteristics of the inlet is significant: the appearance, development and disappearance of the low flow-speed area caused by the movement of the solid wall would alter the aerodynamic characteristics of the 2D hypersonic inlet.

Key words: hypersonic inlet, angle of attack, unsteady, unstart, numerical simulation